<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>理想视口</title>
	<meta name="viewport" content="width=device-width"/>
	<style>
		*{
			margin: 0;
			padding: 0;
		}
		#demo{
			width: 375px;
			height: 375px;
			background-color: skyblue;
		}
	</style>
</head>
<body>
	<div id="demo">你好</div>
	<script type="text/javascript" >
		console.log('布局视口宽为：',document.documentElement.clientWidth)
		console.log('视觉视口宽为：',window.innerWidth)
	</script>
</body>
</html>